Problem: Drain Hole
Use your finger or a pencil to carve a riverbed into the sand, as shown in the image. The groove should be approximately 2 centimeters deep and 2 centimeters wide. Be sure that the groove does not expose the bottom of the tray. Invert and gently squeeze the water bottle so water flows into the beginning of your river. Create a steady stream, but not a flood!
You'll notice that the water seeps into the sand instead of running along the top, like a river or a stream. This phenomenon also happens on Earth's surface in the water cycle. Explain which steps of the water cycle are being modeled as the water soaks into the sand.